Method and device for converting a flat blank into a cellular structure



Nov. l5, i969 M WILLIAMSON 2,960,014

METHOD AND DEVICE FOR CONVERTING A FLAT BLANK INTO A CELLULAR STRUCTURE Filed Dec. l2, 1957 8 Sheets-Sheet 1 Fig. I

l N VEN TOR. Marsh a/ l M//zamsofz' M ATTORNEY Nm?. l5, 1950 M, L WILLIAMSON 2,960,014

METHOD AND DEVICE FOR CONVERTING A FLAT BLANK INTO A CELLULAR STRUCTURE Filed Dec. l2, 1957 8 Sheets-Sheet 2 INVENTOR. Mars/ml! Wz/llkzmson "l ATTORNEY Nov. i5, 1960 M. l. WILLIAMSON 2,960,014

METHOD AND DEVICE FOR CONVERTING A FLAT BLANK INTO A CELLULAR STRUCTURE Filed Dec. l2, 1957 8 Sheets-Sheet 3 I N V EN TOR. Mars/7a!! Wzl/amaai? NMA 5, 1950 M. l. WILLIAMSON 2,969,914

METHOD AND DEVICE FOR CONVERTING FLAT BLANK INTO A CELLULAR STRUCTURE Filed Dec. l2, 1957 8 Sheets-Sheet 4 IN VEN TOR. Marsha/l I. WzY//amson BY #mv-Md" 5. IW

Nov. 15, 1960 M. l. wlLLlAMsoN 2,960,014

METHOD AND DEvxcE Foa coNvERTING A FLAT BLANK INT0 A CELLULAR STRUCTURE Filed Deo. 12, 1957 8 Sheets-Sheet 5 j?? /0 INVENToR.

' Mars/zal! I Williamson lul ATTORNEY Ncv. 15, 1960 M. l. WILLIAMSON 2,960,014

METHOD AND DEVICE FOR CONVEETING A FLAT BLANK INT0 A CELLULAR STRUCTURE Filed Dec. l2, 1957 8 Sheets-Sheet 6 F /2 INVENToR.

y Marsha/l Wil/lam .son

#rw-MA- lav-vul( HPPER FEEDER Nov. 1.5, 1960 M. I. WILLIAMSON METHOD AND DEVICE FOR CONVERTING A FLAT BLANK INTO A CELLULAR STRUCTURE SLEEVE EXPANDERS 8 Sheets-Sheet 7 CASE EJECTORS CASE ELEVATOR TIPPERS 85 GLUE WHEELS 3RD CHAIN CONVEVOR LAMP SEATERS IN VEN TOR. Marsh a!! Wfl/mmso/z LL. ATmR/vfy M. l. WILLIAMSON Nov. 15, 1960 2,960,014 METHOD AND DEVICE FOR CONVERTING A FLAT BLANK INT0 A CELLULAR STRUCTURE 8 Sheets-Sheet 8 Filed Dec. l2, 1957 @HEMONDHQHQ DQQAPU ill...

I mmamOI IN VEN TOR. Marsha/l f. Williamson 4M ATTORNEY Unit@ Marshall I. Williamson, New Haven, Conn. (111 Deerfield Court, Gradeli, NJ.)

Filed Dec. 12, 1957, Ser. No. 702,360

17 Claims. (Cl. 93-37) This invention relates to the manufacture of multicellular structures of paperboard.

Multicellular structures of paperboard serve a great number of purposes and are used, for example, for the packaging as a sales unit of a plurality of articles, such as cans, bottles, jars, packages. The cushioning construction of multicellular paperboard structures is of value in the packaging of fragile or otherwise delicate or easily damaged merchandise, such as glass ornaments, light bulbs, eggs or fruit. The decorative aspects of multicellular packages are an outstanding feature in the packaging of golf balls, chocolates and other merchandise.

The invention provides improvements in the method of forming or assembling multicellular structures and improvements in mechanical devices or machines for forming such structures in an automatic or semiautomatie manner.

The multicellular structures may be in the form of complete boxes, may have the form of trays, or be in the form of inserts for use in separate box structures.

It has been proposed to form cells in an appropriately cut and scored panel by driving a plunger through the panel to deflect portions of the panel into an angular position with respect to the remainder of the panel to form cell-separating webs. One of the problems encountered in this connection is the support of the remainder of the panel, so as to prevent its collapse when the plunger forms the webs. In long boxes or tray structures in whichfour, six or more cells are arranged in line the underside of the panel is not readily accessible for support between the cells because of the presence of vthe box or tray bottom. For this reason considerable States Patent() difficulties are encountered in the use of preglued tubular blanks which are designed for assembly into cellular box form by first squaring the blank and then forming cells in one or several of its panels.

Collapse of portions of the cellular panel which must resist collapsing results in a misshapen structure, jamming of the assembly device and other operational difficulties which this invention prevents.

The various features, objects and advantages of this invention will become apparent from a consideration of the following description accompanied by drawings showing, for the purpose of illustration, an application of the invention to the formation of a multicellular box structure for photographic flash bulbs. In the description and in the drawings specific structural details are described and shown for the purpose of explanation of broader aspects of the invention. It is therefore understood that the details of the invention may be modified in various respects for adaptation to specific forms of cellular structures or specific uses. Such modifications do not involve a departure from the basic principles of the invention and will readily occur to persons skilled in the art. The present invention, however, is not limited to the specific forms shown and described, but consists in certain combinations of elements, steps and sequences of steps of a method as hereinafter set forth in the claims.

The invention applies equally to large scale production in which fully automatic machinery is used as to small scale production in which semiautomatic machines or jigs are used for carrying out the assembly procedure provided by this invention.

In the drawings:

Fig. 1 is a plan view of a typical at blank of a multicellular tray or sleeve;

Fig. 2 is a plan View of the blank of Figure 1 after folding and gluing to form a flat tubular blank;

Fig. 3 is an end view of the liat tubular blank of Figure 2;

Fig. 4 is a perspective view of the completed multicellular tray loaded with ash bulbs, one bulb being removed;

Fig. 5 is a perspective view of an open conveyor section of an automatic assembly machine, the conveyor section being in condition to receive a squared blank;

Fig. 6 shows the conveyor section of Figure 5 in the position in which the blank is grasped and moved into the mouth of a constraining track or passage;

Fig. 7 shows the tubular blank in an advanced position in the track or passage resulting in gabling of the cellular top panel of the blank;

Fig. 8 shows the local collapsing of the gabled panel by projections of an overhead conveyor;

Fig. 9 shows the tubular blank during and after the formation of the cells;v

Fig. 10 shows the loading station of the machine in which flash bulbs are dropped into the preformed cells;

Fig. l1 shows details of a vbulb centering and seating operation performed while the tray or sleeve is still in the constraining passage; v

Fig. l2 is a perspective end View of the loaded package leaving the machine;

Fig. 13 is a diagrammatic elevational view of an automatic forming and loading machine for ash bulbs incorporating details of Figures 5 to l2; and

Fig. 14 is a diagrammatic plan view of theV machine of Figure 13. Y

In the following description and in the claims parts and elements of the mechanism are identified by specific names 'for convenience, but tit is understood that the names are intended to be generic. Corresponding reference numerals refer to corresponding parts in the several figures of the drawings.

The drawings accompanying, and forming part of, this specification disclose certain specific details of the invention for the purpose of explanation of broader aspects of the invention, but it is understood that the details may be modified in various respects without departure from the principles of the invention and that the invention may be embodied in other structures than the one shown.

rI`he,'blank A shown in Figure 1 forms the subject matter of a copending application Serial No. 673,002 filed July 19, 1957. It may be cut and scored, in multiple, without waste of stock from rolls or sheets of paperboard and comprises a side panel 11, a top panel 12, a further side panel 13, a bottom panel 14, an inner glue panel 15, an interior panel 16 and a glue lap 17 articulated to one another along fold lines 18, 19, 20, 21, 22 and 23.

The top panel 12 is designed to form a cellular strucvture and is, for this reason, provided with a plurality of The bottom panel 14 is provided with apertures 32 through which the bases of the bulbs to be packaged are accessible, as will later be seen, and the internal panel 16 has star cuts 33 in it to form selffopening and gripping apertures in the internal panel 16. 4The star cuts are preferably supplemented by peripheral folding scores 34.

In the preassembly of the blank A adhesive a is applied to the glue lap 17 and to the terminal portion 'of the wall panel 11 and the blank` is then folded at the fold line 21 to bring the glue lap 17 into adhesive engagement with the Wall panel 13 and folded at fold line 19 to bring the side panel 11 into adhesive engagement with the inner glue panel 15. A collapsed flat tubular blank A results which is shown in Figure 2. The sequence of the panels is apparent from Figure 3.

The flat preglued blank A may be shipped and stored in collapsed condition and may be squared and assembled as a cellular sleeve structure by the steps about to be described without any further gluing operation.

At the start of the operations leading to the formation of the cellular structure, the blank A is squared to bring the side panels 11 and 13 into upright positionk with respect to the bottom panel 14. Preferably, however, and in order to overcome residual resiliency in the several folding scores, the blank is rst recollapsed in the reverse sense, so as to bring the side panel 13 into a position overlying the bottom panel 14, whereafter Y the blank is again squared. The reverse recollecting insures freedom of the tubular structure A from a tendency to lean to one side or the other.

The squared tubular sleeve A" is then fed into a mechanical device in which the cellular top structure is formed. This mechanical device may be of different construction depending on whether it performs fully automatically, semiautomatically, with a plurality of blanks running through it, or Whether it handles one blank at a time.

Common to all these devices is the performance of a series of steps in the formation of the cellular structure, the first of which is the gabling of the top panel followed by a collapsing operation at longitudinally spaced points of the gabled top panel to form the cells. The collapsing operation is performed by a plunger-like mechanism.

-It is evident that for the formation of an accurately shaped structure it is essential that the portions of the top panel which form cell-separating webs and which lie midway between the cuts 25 do not collapse under the action of the plunger-like mechanism. Such undesirable collapsing may conceivably be prevented by an appropriate mechanical support of the web forming portions. This however isfdiicult, if not impossible, to accomplish where access to the undersurface of the top panel is barred by the presence of a bottom panel, an interior panel, or the like.

For this reason the top panel is first converted into a collapse-resistant gable structure, laterally supported to resist collapsing at the web forming areas.

The gabling is performed by exerting pressure against the sides of the top panel resulting in a deilection of the ridge score upwardly.

Referring to Figure 5, the squared blank is inserted into a section 35 of a conveyor chain 36. The section comprises a trailing portion 37 secured to the chain 36 at 38 and a leading portion 39 similarly secured. An intermediate supporting platform 40 may be provided. The section 35 opens to receive or release a blank when the chain 36 passes over a curved path, such as a sprocket Wheel, and grips the blank when the chain passes over a straight path.

For `this purpose the section 35 comprises two blank grasping blocks 41 which are somewhat tapered at the inner ends 42 at which the blocks engage the blanks. The taper extends into the ends ofthe tubular blank whose end edges then come to rest against shoulders 43. rl'he blocks 41 have a recess 44 for clearing the interior panel 16 of the blank and are peaked at 45 in order to raise the center portion of the top panel 12 in preparation of the formation of the aforementioned gable. A recess 46 at the peak provides adequate clearance for the cell forming plungers later to be described. Surfaces 47 at the peak support the underside of the top panel of the blank in gabled position.

Figure 6 shows the blank A grasped between the blocks 41. in the illustrated position the trailing block is nearly in an upright position, but its peaked portion 45 and supporting surfaces 47 have not fully entered the blanks as may be seen from the flat condition of the end portion of the top panel 12. The leading block 41 has fully grasped the leading end of the blank and raised the center portion of the top panel at the point of engagement to form a peak at 31.

The advancing conveyor moves the blank into an increasingly narrowing path or channel which, in the illustrated form of machine, is formed by two opposed rails 48 and 49 having a flaring mouth 50 into which the blank enters. The rails engage the side walls 11 and 13 at the top fold lines 18 and 19 which constitute the lateral edges of the top panel, and exert a substantially horizontally directed compressive force on the top panel causing the top panel to buckle. The buckling occurs in an upward direction by reason ofthe initiation of the deection of the panel 12 by the peaked portion 45 of the leading block 41.

The frictional engagement of the top panel portions at the cuts 24 and a tendency of the board to curve the top panel slightly upwardly by reason of its inherentresistance to folding at the top fold lines 18 and 19 is sufficient to insure consistent upward gabling of the top panel 12 as the blank moves into the increasingly narrower portion of the path between the rails 43 and 49.

Figure 7 shows the blank at a further advanced stage between the rails 48 and 49. At this stage the leading portion of the top panel to about the fourth aperture 25 is gabled and the trailing portion of the blank which is engaged by the trailing block 41 is also raised in gabled position.

The gabled blank now moves into the path of a plurality of plungers about to bear down on, and penetrate, the gable to collapse it at longitudinally spaced points to form individual cells. ln a continuous machine the plungers Sil are mounted on an overhead conveying means which moves the plungers at the same rate of advance at which the conveyor moves while additionally moving the plungers closer towards the conveyor until the plungers collapse the gable.

In the illustrated form of machine the plungers are -ball shaped elements St) mounted on a wheel 51 driven in timed relationship with, and at the same lineal rate of advance as, the conveyor 36.

The plungers 50 bear against the gabled top panel 12 at about the apertures 25 and depress the blank portion about the apertures in the nature of a funnel. This deilection of the engaged top panel portion is aided by the folding scores 26, 27, 28 and 29.

During the collapsing of the cell forming portions of the top panel the side walls tend to bulge out substantially in line with 'the cuts 24. In order to permit such bulging out, relief recesses 52 and 53 are provided in the rails 48 and 49.

Figure 9 shows the blank in the position in which a plunger is about to enter `the last cell portion of the blank, the first cells having been formed. The top panel 12 adjacent the first and last cell portion is supported against collapsing by the surfaces 47 of the blocks 41. At the illustrated stage the top panel 12 is still under lateral compression between the rails 48 and 49.

It is readily seen that the degree of lateral compression determines the size of the opening of the cells. This i feature is taken advantage of in the filling or loading of the cellular structure. Figure shows the loading station of the machine, details of the conveyor mechanism which feeds the flash bulbs being omitted for the sake of clearness.

The flash bulbs 54 are dropped, base first, into the prepared cell openings of the folding box structure, bulbs being shown in the first three cells. The bulbs 54 still protrude above the cell separating webs 55 of the box, since the wall portions of the cells are still in funnel-like position, i.e. less than fully deflected. Full defiection of the side portions of the cells occurs when the bulbs 54 are being fully seated.

This operation is illustrated in Figure 1l in which the box structure is shown after removal of four bulbs from the last four cells to illustrate the opening and closing action of the cell structure more clearly.

Full seating of the bulbs involves insertion of the bulb bases into the star-cut openings 33 of the interior panel 16 (see also Figures 4 and l2). The star-cut openings fit the bulb bases snugly and it is therefore important to center the bases properly over the holes prior to pressing the bulbs fully into the cells.

rhis is accomplished by a widened portion of the passage between the rails 43 and 49 at 56 and 57. At this point the compressive pressure on the top panel is relieved somewhat, causing the cells to close to some degree, as shown at 58. The closing of the cell accurately centers the bulb base over the respective star-cut in preparation of the engagement of the bulb by a device for fully inserting the bulb into the cell.

This device is shown in Figure l1 as being in the form of a second wheel 59 having a plurality of hollow cylindrical plungers 6i) at its periphery which engage the bulbs and press vthem down into the respective cells.

At the station at which the bulb is being fully seated the rails 48 and 49 may be provided with even wider recessed portions 61 and 62 to permit temporary bulging out of the side walls.

The filled cellular structure is then discharged from the rails 48 and 49 as shown in Figure l2. In this illustration the first bulb of the package was lifted into an elevated position, which it had prior to seating by the wheel 59. This illustrates the degree of movement performed by the seating operation. The second bulb of the package is shown in fully seated position, its base being accessible through the respective aperture 32 in the bottom 14. Y

Figures 13 and 14 show in diagrammatic form a completely automatic machine for forming and filling cellular cartons resulting in the formation of twin packages having a capacity of twelve bulbs. In the machine two cellular sleeves are set up, formed and filled simultaneously.

Two hoppers 63 and 64 supply preglued tubular flat blanks A which are squared and fed into a pair of first conveyors 65 trained around sprocket wheels 66 and 67. The first conveyors move the blanks past stations 69 and 69' at which the blanks are collapsed in the opposite direction as previously explained, and then squared at 70, whereafter the squared blanks move into the reach of the second pair of conveyors 36 extending about sprocket Wheels 67 and 68.

The second conveyors 36 move the blanks past the gabling and web forming stations 71 and 72, the station 71 being characterized by the narrowing passage defined by the rails 48 and 49, the station 72 comprising the plunger wheel 51 driven over a chain 73 and gear train 7 4, 75 from the conveyor 36.

Bulb delivery conveyors 76 extending from a lamp machine (not shown) deliver bulbs into a position above the cellular sleeve structures where the bulbs are dropped into the preformed cells at a loading station 77. The bulbs are then seated at an inserting station 78 characterized by an overhead conveyor S9' having plungers 60' n? driven over a chain 79 and a gear train 80, 81 from the conveyor 36.

The loaded sleeves then pass over a glue wheel 82 after moving into the reach of a pair of third conveyors 83 extending over sprocket wheels 68 and 84. The glue wheel applies spots of adhesive to the underside of the bottom panel 14 of the loaded sleeves. The sleeves are then tipped over on their sides at a tipping station 85. The loaded cellular box structures finally ymove into the grip of pressure belts urging the bottom panels together resulting in the formation of a twin package 87 at the end of the conveyor ready to be fed into a conventional case loader 88.

What is claimed is:

1. The method of converting a tubular blank of substantially rectangular cross section and having an originally iiat top panel traversed by transverse cuts and scores into a multicellular structure, which includes the steps of first gabling the top panel longitudinally; and then collapsing the gabled top panel at longitudinally spaced points to produce transverse webs.

2. The method of forming individual cells in an initially flat panel having transverse cuts and scores .which includes the steps of first displacing in one direction the center portion of the panel With respect to its lateral portions; and then locally collapsing in the opposide direction the top panel by application of pressure at longitudinally spaced points of the center portion.

3. The method of forming individual cells in an initially at panel having transverse cuts and scores which includes the steps of first displacing in one direction the center portion of the panel With respect to the lateral portions to form a gable; and then locally collapsing in the opposite direction the gabled top panel by application of pressure at the gable at longitudinally spaced transverse cuts to displace the portions of the blank adjacent said cuts into an angular position with respect to the remainder of the top panel.

4. The method of converting a tubular blank of substantially rectangular cross section and including an originally flat top panel traversed by transverse cuts and scores into a multicellular structure which includes the steps of tlrst laterally compressing said top panel to buckle the center portion of the panel in one direction in such a way as kto form a gable; and then while maintaining the compressive force on the top panel applying force in the opposite direction against the gabled center portion at longitudinally spaced cuts to displace the portion of the blank adjacent such cuts into an angular position with respect to the remainder of the top panel, forming transverse webs.

5. The method of converting a tubular blank of substantially rectangular cross section and including an originally at top panel traversed by transverse cuts and scores into a multicellular structure which includes the steps of first laterally compressing said top panel to buckle the center portion of the panel in one direction in such a way as to form a gable; and then applying force in the opposite direction by forcing a plunger through the gabled panel at longitudinally spaced cuts to displace the portions of the blank adjacent such cuts into an angular position with respect to the remainder of the top panel to formtransverse webs, and simultaneously relieving the lateral compression force substantially in line with said cuts to permit local bellying-out of the blank at the ends of the cuts during entry of the plunger.

6. The method of converting a tubular blank of substantially rectangular cross section and including an originally fiat top panel traversed by transverse cuts and scores into a multicellular structure which includes advancing said blank longitudinally and applying a compressive force against the longitudinal sides of said top panel, thereby causing the central portion of the blank to buckle and be displaced in one direction forming a gable; then applying a collapsing force in the opposite direction against and through the gable at longitudinally spaced cuts to collapse said gable locally by displacing the portions of the blank adjacent said cuts into an angular position with respcet to the remainder of the top panel; and simultaneously relieving the lateral compression force substantially in line with said cuts to permit local bellying-out of the blank at the ends of the cuts.

7. The method of converting a flat panel of a blank of foldable sheet material traversed by transverse cuts and folding scores into a multicellular structure which comprises the steps of first applying compressive pressure against the sides of the panel to cause it to buckle and form a longitudinal gable; then collapsing the gabled panel locally at longitudinally spaced points by pressure exerted against the gable, thereby displacing portions of the panel into angular web-forming position; and simultaneously supporting the ends of the blank from the underside against collapse.

8. The method of converting a flat panel of a blank of foldable sheet material traversed by transverse cuts and folding scores into a multicellular structure which comprises the steps of first applying compressive pressure against the sides of the panel to cause it to buckle and form a longitudinal gable; initiating the formation of said gable prior to the application of said compressive pressure by upwardly displacing 'the ends of the blank intermediate the sides and then supporting the ends of the blank in such displaced position from the underside; and then collapsing the gabled panel locally at longitudinally spaced points by pressure exerted against the gable, thereby displacing portions of the panel into angular web-forming position.

9. A device for converting a flat panel including trans- Verse cuts and folding scores into a cellular structure comprising transverse webs formed of portions of said panel, the device comprising, in combination, a pair of oppositely disposed rails for contacting the sides of the panel; means supporting said rails at a Vdistance from each other less than the width of the panel so as to buckle the panel; means centrally located between said rails for engaging the underside of said panel at the ends of the panel and supporting the buckled central blank portion by :forming a gable; spaced plungers; and 'means for moving said plungers against the ridge of the gabled panel and into the gable for collapsing said gable at spaced points to flex portions of the panel into an angular position with respect to the remainder of the panel.

l0. A device for converting a flat panel including transverse cuts and folding scores into a cellular structure comprising transverse webs formed of portions of said panel, the device comprising, in combination, a pair of oppositely disposed converging rails defining an increasingly narrowing path between them including a path prtion narrower than said panel; conveyor means for advancing the panel into said path in lateral engagement with said rails into said path portion; means for centrally engaging the underside of the ends of the panel for deecting the central panel portion upwardly, thereby gabling the panel to fit the narrowing path; spaced plungers above said path; and means for moving said plungers against the ridge of the gabled panel confined between said rails to collapse said gable at spaced points to flex portions of the panelinto an angular position with respect to the remainder of the panel.

ll. A device for converting the flat top panel of a tubular blank into a cellular structure, the top panel being provided with transverse cuts and folding scores, the device comprising, in combination, means including two oppositely disposed converging members defining a lateral track of increasingly narrowing width between them including a track portion narrower than said panel; first conveyor means for advancing the squared tubular blank along said track in lateral engagement with said converging members into said narrow track portion; means for centrally engaging the underside of the ends Vof said panel for deflecting the central panel portion upwardly, thereby gabling the panel to fit the narrowing track; second conveyor means above said track, said second conveyor means approaching said first conveyor means in the direction of the narrowing path; and spaced projections on said second conveyor means for bearing vagainst and penetrating the gabled panel to collapse said panel at spaced points, thereby flexing portions of said panel into angular position with respect to the remainder of the panel.

l2. A device for converting the fiat top panel of a tubular blank into a cellular structure, the top panel being provided with transverse cuts and folding scores, the device comprising, in combination, means including two oppositely disposed converging members defining a lateral track of increasingly narrowing width between them including a track portion narrower than said panel; first conveyor means for advancing the tubular blank along said track in lateral engagement with said converging members into said narrow track portion; panel engaging means on said conveyor for engaging the underside of the ends of the panel, said engaging means being shaped to deflect the ends of the panel centrally upwardly so as to form a gable and support the ends in gabled position; second conveyor means above said track, said second conveyor means approaching said first conveyor means in the direction of the first conveyor means and moving at the same linear velocity as the first conveyor means; and spaced projections on said second conveyor means for bearing against and penetrating the gabled panel within said narrow track `portion to collapse said panel at spaced points, thereby -liexing portions or" said panel into angular position with respect to the remainder of the panel.

13. A device for converting the fiat top panel of a tubular blank into a cellular structure, the top panel being provided with transverse cuts and folding scores, the device comprising, in combination, means including two oppositely disposed converging members defining a lateral track of increasingly narrowing width between them including a track portion narrower than said panel; first conveyor means for advancing the squared tubular blank along said track in lateral engagement with said converging members into said narrow track portion; means on said conveyor for centrally engaging the underside of the ends of said panel to defiect the panel portionvupwardly, thereby gabling the panel to fit the narrowing track; second conveyor means above said track, said second conveyor means approaching said first conveyor means in the direction of the narrowing path; and spaced projections on said second conveyor means for `bearing against and penetrating the gabled panel within said narrow track portion to collapse said panel at spaced points, thereby flexing portions of said panel into angular position with respect to the remainder of the panel, said converging members including lateral opposite recessed portions located in line with the point of entry of the said projections into the gable, said recessed portions permitting local bellying-out of the blank during entry of a projection into the gable.

14. A device for converting the flat top panel of a tubular blank into a cellular structure, the top panel being provided with transverse cuts and folding scores, the device comprising, in combination, means including two oppositely disposed converging members dening a lateral track of' increasingly narrowing width between them including a track portion narrower than the panel; first conveyor means for advancing the squared tubular blank along said track in lateral engagement with said converging members int-o said narrow track portion; means on said first conveyor for centrally engaging the ends of said panel at the underside for defiecting the panel upwardly, thereby gabling the panel to fit the narrowing track; a second conveyor opposite said first conveyor and in a path approaching said track; and spaced projections on said second conveyor for bearing against and penetrating the gabled panel within said narrow track portion to collapse said panel at spaced points, thereby ilexing portions of said panel into angular position with respect to the remainder of the panel.

15. A machine for converting into a multicellular structure a tubular squared blank comprising upright side walls, a bottom articulated to the side walls along bottom fold lines, and a top panel articulated to the side walls along top fold lines, said top panel having folding scores extending across it and cuts extending transverse of the panel for the formation of cells in line with the cuts, the machine comprising, a conveyor for longitudinally advancing the squared blank, said conveyor comprising leading and trailing lugs for engaging the leading and trailing ends of the squared blank, said lugs having portions for engaging the underside of the ends of the top panel of the blank at its center and raising it above the side fold lines; means forming a passage for the squared blank, said passage comprising a pair of opposite rails substantially at the level of the top panel of the blank, the spacing of the rails within a certain portion being less than the width of the flat top panel, whereby the top panel is put under compressive stress within said portion causing it to buckle and form a gable; plunger means above said conveyor arranged to descend downwardly into said certain space between said tracks, said plunger means comprising individual projections spaced according to the spacing of said cuts, said tracks being provided with lateral relief cut-outs to either side of the station of entry of the plunger projections into the top panel to permit local bulging-out of the sides of the blank at said cut-outs; and means for driving the plunger means in timed relationship to said conveyor.

16. A device for converting into a multicellular structure a tubular squared blank comprising upright side walls, a bottom articulated to the side walls along bottom fold lines, and a top panel articulated to the side walls along top fold lines, said top panel having folding scores extending across it and cuts extending transverse of the 4() panel for the formation of cells in line with the cuts, the device comprising, two opposite rails for engaging the side walls of the blank substantially at the level of the top panel; means for supporting said rails at a distance from each other less than the width of the top panel, whereby the top panel is put under compressive stress causing it to buckle and to form a gable; plunger means above said rails arranged to descend downwardly into the space between said rails containing the buckled blank, said plunger means comprising individual projections spaced according to the spacing of said cuts, said rails being provided in their blank contacting surfaces with lateral relief cut-outs to either side of the station of entry of the respective plunger projection into the top panel to permit local bulging-out of the sides of the blank at said cut-outs.

17. A device for converting into a multicellular structure a tubular squared blank comprising upright side walls, a bottom articulated to the side walls along bottom fold lines, and a top panel articulated to the side walls along top fold lines, said top panel having folding scores extending across it and cuts extending transverse of the panel for the formation of cells in line with the cuts, the device comprising, two end members for engaging the ends of the blank and lifting the top panel portion midway between the side walls above the top fold lines; two opposite rails for engaging the side walls of the blank substantially at the level of the top panel; means for supporting said rails at a distance from each other less than the width of the top panel, whereby the top panel is put under compressive stress causing it to buckle from end to end to form a gable; plunger means above said rails arranged to descend downwardly into the space between said rails, said plunger means comprising individual projections spaced according to the spacing of said cuts, said rails being provided in their blank contacting surfaces with lateral relief cut-outs to either side of the station of entry of the respective plunger projections into the top panel to permit local bulging-out of the sides of the blank at said cut-outs.

References Cited in the file of this patent UNITED STATES PATENTS 30,374 `Crosby Oct. 9, 1860 870,195 Norton Nov. 5, 1907 2,407,253 Conner Sept. 10, 1946 2,605,679 Welsh et al. Aug. 5, 1952 2,615,376 Pelikan Oct. 28, 1952 2,687,069 Burger et al. Aug. 24, 1954 2,815,700 Bowman et al. Dec. 10, 1957 

